Malaria Vector Population Genetic Division and Vector Competence in Hainan Island Project Summary Malaria is a significant public health problem and impediment to socioeconomic development in countries of the Greater Mekong Subregion of Southeast Asia. The tremendous geographical heterogeneity of malaria epidemiology in this region is associated with diverse vector systems with different vectorial capacities for the parasites. As the major measures of malaria control strategies, insecticide-treated bed nets and indoor sprays have resulted in pyrethroid resistance, and greatly reshaped the mosquito community and population structures. In Hainan Island of China, extensive use of insecticides for malaria control has led to an initially sharp decrease and recently rebound of Anopheles miminus, the key malaria vector in China and Southeast Asia. Not only has the insecticide-driven vector population succession restructured the vector community, but also the resurged mosquito population displayed altered biting preference. Based on these observations, we hypothesize that recent intensive malaria vector control measures and agricultural pest control measures have caused a significant ecological species succession and population genetic bottleneck of malaria vectors in Hainan Island, China. Therefore, this FIRCA proposal aims to take the advantage of geographical isolation of Hainan Island to elucidate the evolution of a major malaria vector in response to insecticide control. We will determine whether the different ecotypes of An. minimus from hilly and plain areas have different vectorial competence to Plasmodium falciparum infections. This study will provide invaluable information for the prediction of mosquito evolution in response to insecticides-based mosquito control measures in other malaria-endemic regions of Southeast Asia. The proposed research will contribute to building research capacity by training one Ph.D. student and one postdoc fellow from the endemic country. This project will be carried out primarily in China at Chongqing Normal University in collaboration with Dr. Bin Chen, as an extension of NIH grant U19 AI089672.